Prof. Nicolas Mach

Prof. Nicolas Mach is one of Switzerland's foremost medical oncologists specialising in immuno-oncology, based at the Hôpitaux Universitaires de Genève (HUG) — the university hospital complex of the University of Geneva. Over a career spanning more than 25 years, he has built a practice at the cutting edge of cancer immunotherapy, with a focus on melanoma, non-small cell lung cancer, and renal cell carcinoma.

HUG occupies a uniquely international position among European academic medical centres, situated in one of the world's most cosmopolitan cities and hosting a large proportion of international patients alongside the Swiss population. Within this environment, Prof. Mach leads the oncology immunotherapy programme, overseeing the delivery of checkpoint inhibitor therapies — including PD-1, PD-L1, and CTLA-4 inhibitors — across tumour types, and coordinating a robust portfolio of clinical trials that give his patients access to novel combination immunotherapy strategies.

Prof. Mach's approach to oncology is deeply translational. He works at the interface of laboratory science and clinical medicine, applying insights from tumour immunology — including biomarker analysis such as tumour mutational burden (TMB), PD-L1 expression, and microsatellite instability (MSI) status — to personalise immunotherapy decisions for each patient. He participates in HUG's multidisciplinary molecular tumor board, where complex cases are reviewed by oncologists, pathologists, radiologists, and molecular biologists before a treatment plan is finalised.

As a member of the Society for Immunotherapy of Cancer (SITC) and a Fellow of ESMO, Prof. Mach is active in international scientific exchange and contributes to guidelines, consensus statements, and educational initiatives in immuno-oncology. He is widely respected both as a clinician and as a scientist who has helped shape Switzerland's leadership in cancer immunotherapy research.

Prof. Mach completed his medical degree and doctoral research at the University of Geneva Faculty of Medicine, where he combined laboratory-based tumour immunology research with clinical training in internal medicine and oncology. His PhD thesis laid the groundwork for his subsequent career in cancer immunotherapy, focusing on mechanisms of immune evasion by tumour cells.

He undertook postgraduate clinical training and research fellowships at leading oncology centres in Switzerland and abroad, developing expertise in clinical trial design, immunotherapy administration, and translational biomarker research. He holds the Fellowship of the European Society for Medical Oncology (FESMO) and the degree of PhD from the University of Geneva. His trilingual capability in French, German, and English facilitates both international collaboration and broad patient accessibility.

Prof. Mach's clinical expertise centres on the use of immune checkpoint inhibitors — anti-PD-1 agents (nivolumab, pembrolizumab), anti-PD-L1 agents (atezolizumab, durvalumab), and anti-CTLA-4 therapy (ipilimumab) — in the treatment of melanoma, non-small cell lung cancer, renal cell carcinoma, head and neck squamous cell carcinoma, and urothelial cancers.

He incorporates biomarker-driven patient selection into every treatment decision, using PD-L1 immunohistochemistry, tumour mutational burden (TMB) assessment, and MSI/MMR testing to identify patients most likely to benefit from immunotherapy. Combination regimens — such as ipilimumab plus nivolumab or pembrolizumab plus chemotherapy — are managed with careful attention to immune-related adverse event recognition and management. He supervises clinical trial enrolment within HUG's oncology programme, providing eligible patients access to investigational therapies in early and late-phase trials.

Prof. Mach has authored and co-authored more than 150 peer-reviewed publications in leading journals including the Journal of Clinical Oncology (JCO), Annals of Oncology, Cancer Immunology Research, and Nature Medicine. His early work on ipilimumab and nivolumab in advanced melanoma contributed to the clinical evidence base that led to regulatory approval of these agents in Europe.

His research group at HUG focuses on combination immunotherapy strategies — including immunotherapy with targeted therapy and immunotherapy with radiotherapy — and on the identification of predictive biomarkers that distinguish responders from non-responders. He has been an investigator in multiple international phase II and phase III trials for ESMO, SITC, and industry-sponsored programmes. His translational work bridging laboratory immunology and clinical outcomes has been presented at ASCO, ESMO, and SITC annual meetings.

HUG's position in Geneva — a city with a large international community and diplomatic presence — means the hospital is highly experienced in treating patients from around the world. Prof. Mach consults fluently in French, German, and English, and the hospital's international patient services office provides comprehensive support including translation, insurance coordination, and accommodation guidance.

For patients abroad seeking a second opinion before beginning immunotherapy, video consultations are available to review pathology, molecular testing results, and imaging. Patients considering treatment at HUG can expect transparent communication about expected treatment duration, costs, and monitoring protocols. EU patients can utilise their European Health Insurance Card (EHIC), while private international patients receive dedicated care coordination.

Prof. Mach has been recognised by both Swiss and European oncology communities for his contributions to immuno-oncology research and clinical practice. He has received the Swiss Society of Medical Oncology (SSMO) Research Prize and the HUG Clinical Research Award for outstanding investigator-initiated trial activity. He holds the Fellowship of the European Society for Medical Oncology (FESMO) — a distinction reflecting excellence in oncology across Europe. He has served on scientific committees for ESMO and SITC, contributing to international educational programmes and clinical practice guidelines in immunotherapy.